But in all seriousness... I dunno if you will regret not waiting or not. I have poor impulse control myself. I try to make my purchases to limit the amount of regret that I might potentially have. If i can get a good ratio of speed vs lack of regret, then I am all set.

I had always wanted the 'phone yes, but it was of a lust rather than a purchase. I had set a budget just in case I change my mind but I was going to wait for the SE530 to be available on ebay anyway... But then, I saw a really good deal and I couldn't resist myself from bidding. Won the damn thing on ebay for 270 bucks or 141 pounds, including shipping to the UK. Pretty cheap...

That is a terrific price for those NIB.
For what it's worth, on your first IEMs, work with the fit until you get it right, it costs nothing to experiment (unless you are too rough..) but it can make or break the sound.
Most people need some time to get used to IEMs, so you may not immediately get "blown away", so IMO, wait 1-3 weeks before you make a real judgment about them.

I think you'll be blown away by the e500. I listen to my e4c through my ipod on 320 mp3 and they sound impressive. Sure, it not the whole 9 yards like with my home setup for the k701, but enjoyable no the less. You shouldn't get an amp unless you feel the sq of the e500 is lacking. The when the time comes for an upgrade, you can get the amp.

Whatever happens, please give the IEMs a true shot by not basing your opinion of them on your very first listen. I would say that's true for any ear/headphones. Try them out with different material and sources to truly see how they perform.